Audi A3 2.0 TDI starting issue ..

[samroach]

Hi guys 

I have just bought an audi a3 2..0 tdi (54) that has got a staring problem  when left for approx 12 hours or more (mainly overnight ) , 

first thing in a morning the car needs to be cranked over for aprrox 20 to 30 seconds before it fires up , once it has started it will start and run perfectly  until its left again for another long period of time

, i have had it scanned for faultss at an audi garage and the only fault that came up was a low reading from the MAF sensor .

The guy told me to blank off the egr valve as a starting point , i put a blanking plate in and waited till the next morning and the car was still the same and not wanting to start for again around 20 to 30 seconds but starts first turn of the key after the initial start . . 

it runs 100% with no issues once started , 

i Have been looking on forums for days with not much joy , my thinking now after lots of trawling makes me think that the fuel is going back down the lines , whats your thoughts guys ? is there a way i can check or test this before i either set fire to it or take it for an expensive repair which i could do without ... i have tinkered with engines etc before but the tech on these cars can be a little intimidating .. any advice links or videos etc will be gratefully recieved ...  im on stand by with tools in one hand and a match in the other depending on replys lol ... 

 

the  hpfp is a bosch fitted to the end of the camshaft i believe on the right hand side of the motor as you look at it from the front  to the left of the battery .. as i say once running its as sweet as a nut

 

                                          Cheers sam

[Steve Q]

Hi Simon, 

I'm assuming it's been recently serviced? 

It might be worth looking at the glow plugs or leads. 

Cheers

Steve

[Dan3222]

You answered my suggestion with the fuel running back to the tank. Have you left it over night with a full tank of fuel? Also if you can leave it parked (with full tank and the front pointing down hill. This should help with the symptoms if it is fuel starvation.

might be worth pricing up a new pump for the tank. They are a common fault on VWs especially in the Transporters which I have more experience with. I would assume they are using similar ones. It’s these that fail and fuel siphons back.

worth a try anyway.

[samroach]

Hi Dan 

thanks for the input , based on what you say do you think it would be worthwhile me putting a 1 way valve valve into the fuel line as a quick fix ?

[Magnet]

Hello Simon,

If this was my car, I would be taking it to a trusted local diesel specialist (taxi drivers are usually a good source of such recommendations). They normally carry out a fairly simple ‘leak back’ test, (and others)  which could be helpful judging by your symptoms. 

Kind regards,

Gareth.

[samroach]

Hi gareth

i have got it booked into http://www.patkins.co.uk/contact-us.html on the 19th of this month , im just wanting to know if anyone has had a sinilar problem/cure that i might be able to do in the meantime 

[cliffcoggin]

If fuel is running back to the tank overnight, it would be worth turning on the ignition the next day and waiting 30 seconds for the fuel pump to pressurise the injectors before cranking the starter motor. It won't get rid of all the air but it will ease the load on the battery.

[Magnet]

Hi Simon, 

Are Patkins diesel specialists?

Kind regards,

Gareth. 

[Dan3222]

I wouldn’t advise fitting a none return valve until u know u have an issue. Magnets advice is probably best advice in fairness. 

I have had several vehicles with syphoning back to the tank, my mate has this issue with his Landrover Disco. I told him to keep his tank full and point the front down his driveway. He has been doing this for nearly 6 months now and he gets no issues starting. (His issue is not totally curable with a none return valve though). However, this technique can help diagnose the issue but not the exact cause.

Cliffords advice is not quite correct (though I am happy to be corrected and eat my humble pie), diesels rely on a mechanical pump to pressurise the fuel to the injectors, on your car I am sure it is a tandem pump.  The primary pump (the electric one in the tank) actually only runs for about 5 seconds, it’s purpose to ensure fuel is delivered to the fuel filter, the tandem pump then takes over. However, his advice is correct but to do this you will have to turn ignition to second position, count 5 then switch off, again turn to position 2, count 5 seconds and repeat. Do this several times and then see if she starts better. 

I would be very interested to hear however, what the garage says!

[samroach]

hi Dan and thanks guys for the input 

the car has been stood since weds so i expected to be turning it over for a while before she started ... i did as you guys said and turned the ignition on several times and let the fuel tank pump do its stuff and as if by magic it started straight away .

. i bought a gasket and seal kit for the tandem pump so i have took the pump off and fitted the seals rather than send them back as it cant do any harm 

now back to the to the fuel pump in the tank ... you guys have any suggestions as to the problem and cure for it ? 

[cliffcoggin]

20 hours ago, Dan3222 said:

 

 The primary pump (the electric one in the tank) actually only runs for about 5 seconds, 

I didn't know there was a time limit on the electric pump. Thanks for that information Dan.

[cliffcoggin]

2 hours ago, samroach said:

 

now back to the to the fuel pump in the tank ... you guys have any suggestions as to the problem and cure for it ? 

From a purely theoretical aspect, (having worked a bit in chemical engineering,) I would expect the pump to have non-return valves integral to its design. I would have a look while the pump is off the car.

[samroach]

Hi All

 

this morning after being stood for 5 days and doing the turning the ignition on half a dozen times before starting it seemed to work , i have refurbed the vacuum pump and refitted it all and again it fired into life after i fitted it ... i left it a good 4 hours and i went to go out in it and it took a little bit of cranking , im guessing its maybe still bleeding back somewhere , 

does anyone know what the procedure is or have any links pictures etc for checking for air leaks showing which pipes i need to be looking at as im not convinced its cured .... i have just filled the tank to the brim to see if it starts first thing tom but any input would be appreaciated .. i will post some pictures of my pipe set up if that will help show me which pipes i need to check 

 

                                                  thanks again Sam

[Dan3222]

On 3/9/2019 at 7:02 PM, cliffcoggin said:

From a purely theoretical aspect, (having worked a bit in chemical engineering,) I would expect the pump to have non-return valves integral to its design. I would have a look while the pump is off the car.

Certainly on the VW T5 primary pump, the none return valve is built in and it’s this that fails. So a pretty good guess it’s the same with the Audi. 

Its alway awkward though giving advice on a car that you don’t own or have experience with. Never want to say go buy that item and it will sort it. But 😬 I would be buying the primary pump as my first port of call. I would do this because I choose not to take my vehicles to a garage if I can. Sam, you seem hands on though!?! 

[Dan3222]

Any progress Simon?

[samroach]

hi dan / guys 

 

well an update to my starting dilema , i rang a recommended  local diesal specialist and told them the issue and what i had done already ( had it scanned for faults of which there was only a low reading from the MAF  and refreshed  the vacum pump gaskets and seals and changed the fuel filter ) they said to book it in for them to check the fuel system ,   i booked it in for weds last week ...

 

they ran there tests  and found no problem with the fuel sytem and suggested to replace the injector seals , the diagnostic test cost me £60 and i agreed to the injector seals work to be carried out as he was pretty sure it was that .. the work was carried out weds and they wanted to keep it overnight to see if it started the next day , i got a call thursday morning and was told the seals had hardened and the  car had been sorted and ready for collection ,

i went to pick the car up after work and payed the bill of £260 and the car started after a few seconds   , i went out to the car friday morning and decided to go to work in the car and yes it was the same as before it went and taking roughly 10 seconds to fire up , i tried it saturday morning and it fired into life  , saturday evening it didnt want to start again , sunday morning  it took over 10 seconds , i went out in it sunday to a friends 18 miles away , called for breakfast with no starting  issues , i dropped my friend off spent approx and hour there and it struggled to start which was unusual as once it started in a morning it usually didnt have a problem till left over night ,

i arrived home and parked the car up today (sunday) around 5.30 pm , before turning into bed tonight (11.30) i went out to try it and again wouldnt start after a good 10 seconds i decided to abort trying and went to bed a little brow beaten , to say its !Removed! me off is an understatment , i really dont know what to do at this stage and can ill afford to keep throwing good money after bad  , i will be ringing the diesal place tom to see what they say because im £260 out of pocket with the same issue , i did tell them i chose them from the recommendations as i didnt want to take it to a back street garage and have them second guessing and end up replacing this that and the other which is basically whats happened ,   

 

has anyone got any input before i invest in a gallon of petrol and a box of matches 

[cliffcoggin]

Well if the fuel system is OK, (and I'm not entirely convinced it is,) perhaps it's time to look at other faults such as engine compression, air filter, electronic control unit etc. 

[Magnet]

Hello Simon,

Sorry to hear your problems are continuing, and indications are that the work carried out, might not have been as thorough as you would have hoped for. I’m not too familiar with diesels, but I believe one of the basic tests normally carried out is a leak-back test ( I believe it’s called ) which takes in the serviceability of the injectors. Did they carryout this test?

If this was mine then I would be going forward from here by following my earlier advice , and seeking recommendations from your local taxi chaps - ask a few. These folks need reliable and competitively priced service, and their recommendations are generally sound. It’s time to worry If they come up with the same place you have tried!

I had the same issue with a BMW engined Freelander, and this turned out to be a couple of injectors. 

Kind regards,

Gareth. 

[Dan3222]

Yeah I agree, rubbish paying out so much for same problem. TBH these engines start quite well without even using the glow plugs so I would rule them out for now. Last thing you could do yourself is actually clamp the fuel return hose as soon as you stop the engine. Then take this off before cold starting the next day. This should help rule out fuel running back to tank.

If not as Magnet (this chap should be on every forum!!) suggests injector seals could well be the cause, if not it’s the primary pump (in the tank), maybe faulty injector loom or faulty tandem pump.

All these things should be testable by a diesel specialist however, though maybe not the injector seals.

In the mean time put an injector cleaner in the tank, something like millers. This will help somewhat plus you will get the money back in better economy.

[samroach]

On 3/8/2019 at 10:36 PM, Dan3222 said:

I wouldn’t advise fitting a none return valve until u know u have an issue. Magnets advice is probably best advice in fairness. 

I have had several vehicles with syphoning back to the tank, my mate has this issue with his Landrover Disco. I told him to keep his tank full and point the front down his driveway. He has been doing this for nearly 6 months now and he gets no issues starting. (His issue is not totally curable with a none return valve though). However, this technique can help diagnose the issue but not the exact cause.

Cliffords advice is not quite correct (though I am happy to be corrected and eat my humble pie), diesels rely on a mechanical pump to pressurise the fuel to the injectors, on your car I am sure it is a tandem pump.  The primary pump (the electric one in the tank) actually only runs for about 5 seconds, it’s purpose to ensure fuel is delivered to the fuel filter, the tandem pump then takes over. However, his advice is correct but to do this you will have to turn ignition to second position, count 5 then switch off, again turn to position 2, count 5 seconds and repeat. Do this several times and then see if she starts better. 

I would be very interested to hear however, what the garage says!

On 3/8/2019 at 8:05 AM, Magnet said:

Hi Simon, 

Are Patkins diesel specialists?

Kind regards,

Hi guys 

Hi guys 

Took the car in yesterday and just had a call and they cant find anything wrong on the fuels side .. there suggesting it could be the injector seals so I have giv

 

[samroach]

Hi guys 

Latest update on my Audi a3 20tdi 

I parked it facing uphill and noticed that the car struggles to start .. so I borrowed a set of ramps as my street is flat and reversed the car up them so it was facing downhill I went to it this morning after being parked on them all night and it fired into life straight away .. I will try it again later after work and see of it starts which I think it will .. then I'm.going to drive it up the ramps (facing up ) and try it again which I'm.confident from the 2 occasions it's been parked uphill and struggled to start... 

If this is the case where should I focus my attention ? 

[Magnet]

Apologies for being direct Simon, but since you ask where you should focus your attention, I can only reinforce the suggestion of readdresing this with well trusted diesel specialists  - or carry a set of ramps around with you and continually run it up on these. 

Good luck in sorting it out.

Kind regards,

Gareth. 

[Dan3222]

Magnet has a point actually, it has been tested by a derv specialist!?! 

This is where it gets difficult for a joe bloggs giving advice to a Sam Smith where to spend some money. But if I was in your shoes right now this is what I would do.

Park car nose down for at least 3 consective nights, if it starts no issues it pretty much proves fuel running back to tank issues.

Next if you want to, clamp the fuel return pipe coming from the filter. Leaving car parked flat. Remove clamp in the morning, see how she fires up.

these tests basically also rule out injector seals as the main cause. Though not saying they are 100% fine of course (covering my back there 😬)

All this confirms fuel is eventually losing the vacuum that keeps it in the pipes and mechanical bits. Now, extrapolating info from other forums, on 1.6,1.9, 2.0 and 2.5 TDI engines fitted to VW, Audi and Seat vehicles, the most common fix is the primary electronic pump fitted in the tank. The non return valve built into it being the issue.

 

Your talking less than £50 for the pump but shop around, e.g

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F162547351547

You might have some negotiation leverage with the firm you spent money with to contribute to the labour of doing this maybe!?!

[samroach]

Hi guys it's been to a diesal specialist .. they said they did a pressure test and all was fine .. they then told me its pointing to them injector seals which I told them.to do which made no difference.. I have had it parked flat and the problem continued.. I borrowed some ramps and reversed the car up them and its started 2 days on the trot with no issues .. it will hopefully be 3rd time lucky Tom.morning Saturday 23rd .. It starts within a split on ramps .. I have changed fuel filter injector seals and refurbed the vacuum pump all making no difference.. the only thing that's made a difference is parking it !Removed! up on the ramps 

[cliffcoggin]

I'm not a diesel specialist, in fact I have had no formal training of any sort in car maintenance; I just learned the hard way over several decades of caring for my cars so make of my opinion what you will.

The evidence to my mind points to the non-return valve in the primary pump not holding. I don't know how easy it is to replace yourself, (it depends on whether there is a access hatch in the boot floor or the fuel tank has to be dropped out,) but at £50 for a new pump I would take the chance rather than rely on the dubious opinion of specialists who are incapable finding the fault.